FR3121625A1 - Bottle intended to contain a product, in particular cosmetic - Google Patents

Abstract

Bottle intended to contain a product, in particular cosmetics Bottle (2) intended to contain a product, in particular cosmetics, the bottle (2) being produced by a coextrusion-blow molding process and comprising a body (5) and a neck (6) surmounting the body (5) and defining an opening (7) of the bottle (2), the body (5) and the neck (6) being formed by a multilayer wall (12) of the bottle (2), the multilayer wall (12) of the bottle (2) comprising at least three superimposed layers including at least one barrier layer (15) sandwiched between an outer layer (16) and an inner layer (17), at least the inner layer (16) comprising a post-consumer recycled polyolefin (PCR) with a melt flow index (MFI) of between 0.50 and 0.85g/10 min (2.16kg/190°C/ATSM D1238 standard). Figure for abstract: figure 5

Description

Bottle intended to contain a product, in particular cosmetic

The present invention relates to the field of the preservation of products, in particular but not exclusively cosmetic, for example coloring or perm formulas in hair care, sensitive to oxidation, comprising for example vitamin C. The invention relates to more particularly a bottle intended to contain a product, in particular cosmetic, as well as a container comprising such a bottle and a cap closing the bottle. The invention also relates to a process for manufacturing such a bottle by blow molding.

In a context of greater attention to the environment, reducing its impact on it becomes an objective in all areas. Thus, using a post-consumer recycled polymer (PCR) for the manufacture of bottles intended to contain products, in particular cosmetics, is one avenue.

However, it is difficult to obtain the same mechanical, waterproofing and/or aesthetic properties by using a post-consumer recycled (PCR) polymer as by using a virgin polymer. This applies in particular with regard to bottles with a multilayer wall made by extrusion-blow molding, that is to say by coextrusion then blow molding, and intended to contain products, in particular but not exclusively cosmetics, which are sensitive to oxidation and/or techniques, such as coloring or perm formulas in hair care. It is thus a question, for these bottles, of preserving and preserving the technical properties of the formula of the product, of the dye which includes specific active ingredients for a specific final rendering.

US Pat. No. 6,592,955 discloses a multilayer hollow body of thermoplastic material intended to form a pipe or filler nozzle for a fuel tank which is obtained by coextrusion then blow molding and comprises an inner layer, in contact with the fuel, comprising a virgin polymer, an outer layer comprising a virgin polymer and at least one layer, in contact with the outer layer or the inner layer comprising a recycled plastic material.

We know from EP 0 826 487 a multilayer hollow body made of synthetic material obtained by an extrusion-blow molding technique intended for the production of a canister for the packaging of liquids for industrial use. Such a hollow body comprises a layer of barrier material, a layer of adhesive, a layer of a virgin resin providing mechanical strength to the hollow body, a layer of crushed and recycled synthetic material and a film of a synthetic coating material .

There is a need to have a multilayer bottle made by coextrusion-blow molding which contains at least one post-consumer recycled (PCR) polymer and which has properties equivalent to those of such a bottle made entirely with one or more virgin polymers.

The present invention meets all or part of this need thanks to a bottle intended to contain a product, in particular cosmetic, the bottle being produced by a coextrusion-blow molding process and comprising a body and a neck surmounting the body and defining an opening of the bottle, the body and the neck being formed by a multilayer wall of the bottle, the multilayer wall of the bottle comprising at least three superposed layers including at least one barrier layer interposed between an outer layer and an inner layer, at least the inner layer comprising a post-consumer recycled (PCR) polyolefin with a melt index (MFI) of between 0.50 and 0.85g/10 min (2.16kg/190°C/ATSM D1238 standard), in particular between 0.55 and 0.85g/10 min (2.16 kg/190°C/ATSM D1238 standard.

Thanks to the invention, there is a bottle with a multilayer wall produced by coextrusion-blow molding, comprising a polyolefin recycled after consumption (PCR), which has satisfactory mechanical properties compared to a similar bottle comprising a virgin polyolefin.

In particular, the inventors have found that by choosing, in a bottle with a multilayer wall, a PCR polyolefin with a particular MFI, in particular higher than that of a virgin polyethylene which is for example 0.3g/10min (2.16kg/190 °C/ATSM D1238 standard), it was possible to obtain good test results, in particular the alcohol tightness test for 24 hours at 45°C resulting in no leakage and the compatibility test for 2 months at 45°C resulting in no leak following a stress cracking test.

By “inner layer”, is meant the layer intended to be in contact with the product. On the contrary, the “outer layer” refers to the layer farthest from the product, which will be in contact with the outside air and/or a possible product identification label.

To measure the melt flow index MFI, the following protocol can be carried out: in a hopper, we heat in an annular manner to 190°C and we observe what is recovered as a mass of material. The outer layer advantageously comprises a post-consumer recycled (PCR) polyolefin, which post-consumer recycled (PCR) polyolefin is preferably the same as for the inner layer and/or has a melt index (MFI) of between 0.50 and 0.85. g/10 min (2.16kg/190°C/ATSM D1238 standard), in particular between 0.55 and 0.85g/10 min (2.16kg/190°C/ATSM D1238 standard).

The thickness, in particular nominal, of the outer layer forms in particular between 15% and 25%, preferably approximately 20%, of the total thickness of the multilayer wall of the bottle. The thickness is measured on a central part of the bottle extending between a shoulder connecting this central part to the neck and a bottom of the bottle, the shoulder and the bottom not being included for the realization of this measurement.

The thickness, in particular nominal, of the inner layer advantageously forms between 22% and 32%, preferably about 27%, of the total thickness of the multilayer wall of the bottle. As indicated above, the thickness is measured on the central part of the bottle extending between the shoulder connecting this central part to the neck and the bottom of the bottle, the shoulder and the bottom not being included for the realization of this measure.

By adapting the thicknesses, in particular the respective ones, of the layers of the bottle, it is possible to obtain good results in the compatibility and sealing tests. The thicknesses of the layers are preferably adapted for this implementation of PCR polyolefin(s) in the production of the bottle compared to the production of bottles based on virgin polyolefin, so that the bottle remains stable and straight.

The bottle may further comprise an intermediate layer located between the inner layer and the barrier layer, the intermediate layer comprising in particular at least one ground material and one post-consumer recycled (PCR) polyolefin, said post-consumer recycled (PCR) polyolefin being in particular the same as for the inner layer and/or comprises a post-consumer recycled (PCR) polyolefin with a melt index (MFI) of between 0.50 and 0.85 g/10 min (2.16 kg/190°C/ATSM D1238 standard), in particular between 0.55 and 0.85g/10 min (2.16kg/190°C/ATSM D1238 standard).

In this case, the thickness of the intermediate layer forms between 40% and 50%, preferably approximately 45%, of the total thickness of the multilayer wall of the bottle. The thickness is here also measured on the central part of the bottle extending between the shoulder connecting this central part to the neck and the bottom of the bottle, the shoulder and the bottom not being included for carrying out this measurement.

The barrier layer may comprise at least one polymer chosen from the group consisting of EVOH, PVDC, acrylic acid, copolymers of acrylic acid, copolymers of ethylene.

The thickness of the barrier layer can be greater than 2.5% and less than 7.5%, preferably about 5% of the total thickness of the multilayer wall of the vial. The thickness is here also measured on the central part of the bottle extending between the shoulder connecting this central part to the neck and the bottom of the bottle, the shoulder and the bottom not being included for carrying out this measurement.

The multilayer wall of the bottle may comprise at least one adhesive layer, advantageously two adhesive layers arranged respectively on either side of the barrier layer, in contact with the latter.

The adhesive layer or layers can be chosen from the group consisting of general copolymers or an adhesive, such as an ethylene or urethane copolymer for example.

The adhesive layer or layers may comprise an adhesive derived from ethylene, for example that which is marketed under the name Admer® by the company Mitsui Chemicals.

The or each adhesive layer may have a thickness of between 0.5% and 2.5%, preferably being equal to approximately 1.5% of the total thickness of the multilayer wall of the bottle. The thickness is again measured on the central part of the bottle extending between the shoulder connecting this central part to the neck and the bottom of the bottle, the shoulder and the bottom not being included for the realization of this measurement.

The post-consumer recycled (PCR) polyolefin may be selected from the group consisting of post-consumer recycled (PCR) polyethylene (PE), in particular post-consumer recycled (PCR) high-density polyethylene (HDPE), and any type of polyethylene and mixture of polyethylenes.

In this case, when the recycled polyolefin is a post-consumer recycled (PCR) polyethylene, the density of the post-consumer recycled (PCR) polyethylene can be between 0.95 and 0.97 g/cm3, preferably between 0.958 and 0.965 g/cm3.

By "post-consumer recycled polymer", also referred to as polymer recycled after consumption PCR (for "Post Consumer Recycled" in English), is meant a polymer which is the result of recycling, in particular mechanical, or chemical, pyrolytic, enzymatic, carried out on a product used by one or more consumers. Such a PCR recycled polymer is distinguished in particular from a recycled polymer resulting from the grinding of polymer scraps from all the layers of the bottle and generated during the manufacture of the bottle according to the invention, which can also be called "ground material". or “regrind”, and which for example also comprises the barrier layer, for example of EVOH, and the adhesive layer or layers, if present. A recycled polyolefin can be characterized, compared to virgin polyolefin, by the presence of encrustations and/or a specific marker and/or the variation of the MFI melt index

In a particular embodiment, the bottle comprises the following six layers, arranged in this order, from the outer layer to the inner layer with the respective thicknesses indicated, it being understood that the thicknesses are measured on the central part of the bottle extending between the shoulder connecting this central part to the neck and the bottom of the bottle, the shoulder and the bottom not being included for the realization of this measurement:

• outer layer composed of 96% PCR recycled polyethylene and 4% dye or pigment, in particular a colored “masterbatch” (also called “masterbatch”), in particular black, having a thickness corresponding to 20% (+ or – 5% ) the total thickness of the vial,
• adhesive layer, composed of an ethylene derivative marketed under the name Admer®, having a thickness corresponding to 1.5% (+ or – 1%) of the total thickness of the bottle,
• barrier layer comprising an EVOH, having a thickness corresponding to 5% (+ or – 2.5%) of the total thickness of the bottle,
• adhesive layer, composed of an ethylene derivative marketed under the name Admer®, having a thickness corresponding to 1.5% (+ or – 1%) of the total thickness of the bottle,
• intermediate layer comprising a mixture of 35% PCR recycled polyethylene and 65% ground material, having a thickness corresponding to 45% (+ or – 5%) of the total thickness of the bottle,
• inner layer comprising PCR recycled polyethylene, with a thickness corresponding to 27% (+ or – 5%) of the total thickness of the bottle.

A bottle thus produced comprises between 80% and 95%, in particular between 85% and 90%, of recycled polymer including the PCR polymer and the ground material.

The body of the bottle extends between a bottom closing the bottle below and a shoulder connected to the neck.

The total thickness of the wall of the bottle at the level of the shoulder may be between 0.5 and 0.8mm, in particular between 0.59 and 0.75 mm, with an average thickness of between 0.6 and 0.7mm, in particular equal to approximately 0.68mm.

The total thickness of the wall of the bottle at the level of an intermediate part of the body located between the shoulder and the bottom can be between 0.6 and 0.9 mm, in particular between 0.70 and 0.85 mm, with an average thickness between 0. 75 and 0.8 mm, in particular equal to approximately 0.79 mm.

The total thickness of the wall of the vial at the bottom may be between 0.3 and 0.4 mm, in particular between 0.32 and 0.37 mm, with an average thickness of approximately 0.35 mm.

To determine the nature of the layers and the relative thicknesses of the layers of the multilayer wall of the bottle, in particular but not exclusively the barrier layer of EVOH, it is possible to use methods of identification by infrared spectrum and / or by thermal analysis. DSC (Differential Scanning Calorimetry, hence the acronym DSC).

The infrared spectrum identification method consists of choosing one of the known sampling techniques, mainly by solubilization, with toluene or ethylene glycol as solvent, then scanning the wavelengths from 4000 to 600 cm ^-1 . The characteristic absorption bands of the polymers are sought. As for the EVOH, they are found at 3500-3200 cm ^-1 , 2930-2850 cm ^-1 , 1540-1340 cm ^-1 , 1100 cm ^-1 and 840 cm ^-1 .

The method of identification by DSC, a classic method of identification of thermoplastics by DSC is used with the following temperature range scanned: 50 to 250°C. The melting peak temperature is determined. This temperature varies with the ethylene content for the EVOH copolymer according to the following table:

% by weight of ethylene TV (°C) Tm (°C) 21 64 192 26 59 182 30 54 171

The neck is made with the body during coextrusion then blow molding. The neck is not attached to the body after its coextrusion. The bottom is formed by welding (or pinching) a pipe made during coextrusion and before blowing. It should be noted that such a weld should not go up too high on the bottle so as not to increase the risk of cracking, which already increases when using a mechanically recycled PCR polyolefin.

The bottle is distinct from a tube. In particular, the bottle has greater rigidity than that of a tube. The rigidity is obtained by the choice of the polymer or polymers used dictated by the density thereof, and/or by the choice of the thicknesses of the layers. A tube is flexible because it is intended to be squeezed by a user in order to force the product out of the tube through the intended opening defined by the neck of the tube. On the contrary, a bottle is provided to pour the product through the opening defined by the neck of the tube without pressing on the body of the bottle. Furthermore, during manufacture of the tube, the head of the tube (neck) is attached or over-injected onto the extruded part of the tube consisting of a skirt.

To measure the rigidity of a tube, one can implement a test called "hand method of a tube" at the level of the skirt of the latter, which consists in measuring the maximum force applied by the hand to deform a tube and to measure the force applied by the tube after deformation. If the tube remains deformed, the force applied by the tube after deformation, also called “force rebound”, is substantially zero. If the tube regains shape, the “rebound force” is different from zero.

Another subject of the invention, according to another of its aspects, in combination with the foregoing, is a container comprising a bottle as defined above and a closure cap of the bottle configured to cooperate with the neck of the bottle, in particular by screwing, so as to seal the bottle tightly, the closure cap comprising a sealing skirt in contact with the inner side of the multilayer wall of the bottle at the level of the neck, the cap being preferably formed with a recycled polyolefin, including post-consumer recycled (PCR) polypropylene, including by injection molding.

The bottle can house a cosmetic product, in particular a coloring or hair-perming composition.

The volume of product that can be contained in the bottle can be between 20 ml and 2 l, in particular between 20 ml and 1.5 l, for example between 20 ml and 500 ml, in particular between 20 ml and 250 ml, in particular between 20 ml and 100 ml.

It should be noted that for such technical products, it is particularly necessary to ensure a good seal between the closure cap and the neck of the bottle. The use of PCR recycled polymer can have a cracking impact on the sealing skirt when present on the closure cap, knowing that there is strong interference between the bottle and the sealing skirt for this type of product .

Another subject of the invention, in combination with the foregoing, according to another of its aspects, is a method for manufacturing a bottle as defined above comprising the steps consisting in coextruding and blowing said at least three layers in a mold to obtain the bottle comprising the body and the neck.

The method includes the step consisting in welding the tubing produced by coextrusion in order to form the bottom before blowing.

The thicknesses within the extrusion head are preferably adapted to make it possible to obtain the respective predetermined thicknesses of the vial layers indicated above, in particular a greater inner layer thickness than that of the outer layer.

The process according to the invention makes it possible to simultaneously produce the body and the neck in the same die. It is thus not necessary, as is the case for the manufacture of a tube, to add or over-inject a neck on a body after its manufacture.

The implementation of the method may include the step of adjusting, in particular reducing, the temperature in the coextrusion head compared to the usual temperature when the bottle is devoid of PCR recycled polymer.

Such a temperature adjustment can make it possible to contribute to stabilizing the manufacture of the bottle and to obtain a bottle of good quality making it possible to preserve the technical properties and the aesthetic appearance of the bottle.

Thanks to the invention, a bottle is obtained which has good sealing properties and good resistance to cracking.

The invention may be better understood on reading the detailed description which follows, non-limiting examples of implementation thereof, and on examining the appended drawing, in which:

the schematically represents in perspective an example of a container according to the invention,

the represents in isolation, schematically and in partial longitudinal section, an example of a bottle according to the invention,

the shows schematically and in longitudinal section the detail III of the ,

the shows schematically and in longitudinal section the detail IV of the ,

the schematically represents, in longitudinal section, a portion of the wall of the vial of the , and

the schematically shows, in longitudinal section, a portion of the wall of another example of a bottle.

detailed description

In the remainder of the description, identical elements or identical functions bear the same reference sign. For the purpose of conciseness of the present description, they are not described with regard to each of the figures, only the differences between the embodiments being described.

In the figures, the actual proportions have not always been respected, for the sake of clarity.

It has been illustrated at a container 1 according to the invention, comprising a bottle 2 and a closure cap 3 capable of cooperating with the bottle 2 to seal the latter in a sealed manner.

In the example shown, container 1 houses a cosmetic hair coloring product. It has a capacity of 60 ml in the example shown. The capacity may be different without departing from the scope of the invention.

The bottle 2 is largely covered with a label 4 as visible, making it possible to give information on the product, in particular.

As seen on the , the bottle 2 comprises a body 5 and a neck 6 defining an opening 7 of the bottle 2. The body 5 has a central part 8 of general shape, in this example, cylindrical of circular section, extending along a longitudinal axis X. The body 5 comprises, opposite the neck 6, a bottom 9 closing the lower part of the bottle 2. The body 5 comprises a shoulder 10 connecting the central part 8 to the neck 6.

As visible in Figures 2 and 3 and also 4, the neck 6 has an external thread 11 capable of cooperating with an internal thread 30 of the closure cap 3 allowing the latter to be screwed onto the neck 6 of the bottle 2 to close the containing 1.

Figures 3 and 4 show the wall 12 of the bottle at the neck 6 which has, inside the neck 6, a shoulder 13 creating a widening of the inner section of the neck 6 and a narrowing of the wall 12 by moving towards the free end 14 of the neck 6. This shoulder 13 is provided to allow the inner sealing skirt 31 of the closure cap 3, visible on the , to bear against the shoulder 13 and possibly against the wall 12 at the level of the neck 6 in order to ensure the tightness of the closure of the container 1.

According to the invention, the bottle 2 is produced by a coextrusion-blow molding process.

The wall 12 of the bottle 2 is multilayered, as illustrated in the .

The wall 12 of the bottle 2 comprises at least three superposed layers, in the example illustrated in the six layers, including at least one barrier layer 15 interposed between an outer layer 16 and an inner layer 17, intended to be in contact with the product contained in the bottle 2.

The inner layer 17 comprises a post-consumer recycled (PCR) polyolefin having a melt index (MFI) of between 0.50 and 0.85 g/10 min (2.16 kg/190° C./ATSM standard D1238). In the example illustrated, the post-consumer recycled polyolefin is a post-consumer recycled (PCR) high-density polyethylene (HDPE), having a density of between 0.958 and 0.965 g/cm ³ , an MFI of between 0.55 and 0.85 g/ 10 min (2.16 kg/190°C/ATSM D1238 standard), a flexural modulus of 769 MPa and an environmental stress cracking resistance (ESCR) of at least approximately 9 hours.

Other PE PCR polymers can be used for the implementation of the invention. One can for example use a high density PCR polyethylene having a density between 0.95 and 0.965 g/cm ³ , an MFI index of 0.6g/10min (2.16kg/190°C/ATSM standard D1238), a flexural modulus of 1134 MPa and a stress cracking resistance ESCR of at least approximately 8 hours. It is also possible to use a PCR high-density polyethylene having a density of between 0.95 and 0.964 g/cm ³ , an MFI index of between 0.5 and 0.7g/10min (2.16kg/190°C/ATSM D1238 standard), and resistance to stress cracking ESCR for at least about 12.8h. It is also possible to use a PCR high-density polyethylene having a density of between 0.95 and 0.96 g/cm ³ , an MFI index of between 0.5 and 0.7g/10min (2.16kg/190°C/ATSM D1238 standard), and resistance to stress cracking ESCR for at least about 10.8h.

The presence of several layers in the multilayer wall of the bottle can make it possible to obtain better results of resistance to cracking under stress compared to a virgin polymer and also a better preservation of the product contained in the bottle without losing active ingredients necessary to preserve product performance.

The outer layer 16 comprises in the illustrated example a recycled polyolefin, which post-consumer recycled polyolefin (PCR) is in this example the same as for the inner layer 17.

The barrier layer 15 is made of EVOH in this example. The EVOH is preferably a first choice resin, food grade and extrusion grade. It can have a density of 1.19 g/cm3 (ASTM D792 or ISO 1183 standard), an MFR (for "Melt flow rate" in English, that is to say a melt flow index) of between 1 .5 and 2 g/10min (ISO 1133 (190°C, 2.16kg) or ASTM D1238 (190°C, 2.16kg) standards), an ethylene content of 32 mol% (ISO 14663-2 standard), a melting temperature of 183°C (DSC ISO 11357 standard) and oxygen permeability of less than 0.4 cc.20µm/m²/24h atm (ISO 14663-2 (20°C 65%RH) or ASTM D3985 ( 20°C 65%RH)). The EVOH may be that marketed by the company FURARAY under the name EVAL F101A, EVAL F101B or EVAL F171B, or that marketed by the company NIPPON GOHSEI under the name SOARNOL DC 3203FB or that marketed by the company CHANG CHUN (ARKEMA) under the name EV EVASIN 3251 .

The multilayer wall 12 of the bottle 2 comprises in this example two adhesive layers 19 arranged respectively on either side of the barrier layer 15, namely a layer 19a and a layer 19b, in contact with the latter, and comprising in this example the adhesive derived from ethylene marketed under the name ADMER®.

In the example illustrated, the wall 12 further comprises an intermediate layer 18, arranged adjacent and in contact with the inner layer 17, inside the wall 12.

The intermediate layer 18 comprises in this example at least one ground material and one post-consumer recycled (PCR) polyolefin, in this example the same as that of the inner 17 and outer 16 layers.

The thickness of the wall 12 of the bottle 2 and the thickness of each layer of this wall 12 are predetermined and the adjustment of the coextrusion head is provided to make it possible to obtain within 5% of these theoretical thickness values.

In the example illustrated, the relative (predetermined) theoretical values (%) of thicknesses of the various layers with respect to the total thickness of the wall 12 are as follows:

• outer layer 16: 20%
• adhesive layer 19a: 1.5%
• barrier layer 15: 5%
• adhesive layer 19b: 1.5%
• middle layer 18: 45%
• inner layer 17: 27%

In particular, in this example, at least in theory, the predetermined thickness of the inner layer 17 is greater than the thickness of the outer layer 16.

The bottle 2 was produced by implementing the method according to the invention which comprises the steps of coextrusion with a coextrusion head and blow molding in a mold to obtain the bottle 2 comprising the body 5 and the neck 6.

The method further comprises the step consisting in closing the mold parts on the tubing produced by coextrusion, which clamps the tubing at the top and bottom in order to form the bottom 9 before blow molding and welding.

The thicknesses within the coextrusion head are preferably adapted to make it possible to obtain the respective predetermined (theoretical) thicknesses of the vial layers indicated above, with a thickness of the inner layer 17 greater than that of the outer layer 16.

The implementation of the method may include the step of adjusting, in particular reducing, the temperature in the coextrusion head compared to the usual temperature when the bottle is devoid of PCR recycled polymer.

Such a temperature adjustment can make it possible to contribute to stabilizing the manufacture of the bottle and to obtain a bottle of good quality making it possible to preserve the technical properties and the aesthetic appearance of the bottle.

Once the bottle 2 has been made using this process and has cooled, it can be cut to measure the actual thickness of the wall 12 and of each layer of the wall 12 in different places.

A bottle 2 according to the invention was thus produced using the method according to the invention.

This bottle 2 comprises six layers described above forming the wall 12 as illustrated in the and having the respective theoretical thicknesses indicated above and the following characteristics:

• outer layer 16 composed of 96% of PCR recycled high-density polyethylene described above and of 4% of black masterbatch,
• adhesive layer 19a, composed of Admer®,
• barrier layer 15 comprising an EVOH,
• adhesive layer 19b, composed of Admer®,
• intermediate layer 18 comprising a mixture of 35% PCR recycled high-density polyethylene described above and 65% ground material,
• inner layer 17 comprising 100% PCR recycled high density polyethylene.

The PCR high density polyethylene used is the same for the outer layer 16, the intermediate layer 18 and the inner layer 17 in this example.

The table below reproduces the theoretical and measured values of the thicknesses of the different layers forming the wall 12 as well as the theoretical and measured thickness of the wall 12 in different places of the bottle 2.

Average thickness measured Minimum thickness measured Maximum thickness measured Theoretical thickness Outer layer 16 22.11% 20.03% 23.58% 20% Adhesive layer 19a 1.76% 1.14% 2.45% 1.5% Barrier layer 15 5.45% 4.22% 7.11% 5% Adhesive layer 19b 1.70% 1.52% 1.91% 1.5% Middle layer 18 48.33% 44.96% 52.32% 45% Inner layer 17 20.65% 15.74% 26.43% 27% Wall 12 (at shoulder 10) 0.68mm 0.59mm 0.75mm Greater than 0.3mm Wall 12 (at part 8 of body 5) 0.79mm 0.70mm 0.85mm Greater than 0.3mm Wall 12 (bottom 9) 0.35mm 0.32mm 0.37mm Greater than 0.3mm

Thanks to the invention, a bottle is obtained which has good sealing properties and good resistance to cracking, making it possible to obtain good results in the sealing and cracking tests described below.

Test sealing

The articles, approved by Packaging Services, must ensure a good seal. However, certain visual defects that are difficult to see (folds, roughness, glazes in the opening of the bottles, shrinkage on the sealing skirts of the caps, etc.) and certain dimensional deviations can lead to the risk of leakage.

This method makes it possible to check that there are no defects, not observed during the inspection of appearance, affecting the tightness.

The objective of the method is to ensure the proper sealing of the bottle or container, when they are filled with a specific simulant and tested:

- in a vacuum chamber

- in an oven at 45°C

- by means of a leak detector.

The bottle to be tested is filled at the bottom with a defined colored simulant (glycerin, water or colored alcohol). The closure cap is fastened to the bottle and the bottle thus filled is left standing upright for at least 1 hour at laboratory temperature.

To test in a vacuum chamber, the vial to be tested is placed in the chamber in a lying position on white absorbent paper. The pressure inside the enclosure is then brought for 10 to 15 s to a value between 250 and 200 mbar for the manometer with absolute pressure display, to a value between -0.75 and -0.80 bar for the manometer with relative pressure display.

To test in an oven at 45°C (+ or – 2°C), place the bottle to be tested in the oven in the lying position on white absorbent paper and leave for approximately 24 hours (+ or – 1 hour), then it is removed from the oven and placed, head up, at room temperature for at least 2 hours.

To test using a leak detector, a bottle template made with the most unfavorable dimensions is used and it is checked with an absolute test pressure of 150 mbar + or – 20 mbar.

For the interpretation of the results, a critical defect is judged, for the tests in the vacuum chamber or in the oven at 45°C, if the absorbent paper is soiled or if after opening the bottle, it appears that a liquid is present beyond the capsule/vial sealing zone. The allowable leak rate, for the leak detector test, is indicated on the specification sheet or, failing that, the bottle is defective if the leak rate is positive.

Test of resistance to stress cracking or compatibility test

Stress cracking, also called “stress cracking”, is a mode of damage that appears under the combined action of a mechanical stress and a chemical agent. It first causes the appearance of cracks (also called "crazing" in English) and ultimately the rupture of the material (fissuring). The synergy of the two parameters (mechanical stress and chemical agent) makes that the mechanical stress, capable of causing stress cracking, is considerably lower than the breaking stress of the material and the stress cracking can be caused even by a chemical agent. chemical for which the polymer is not sensitive if it is not constrained.

A compatibility test makes it possible to detect this defect or, on the contrary, the resistance to cracking under stress. The resistance to stress cracking can thus be evaluated after conventional compatibility test(s).

To carry out the stress cracking test, a solution of 0.5% + or - 0.05% in m/m of a cracking agent, POLYOXYETHYLENE(12) TRIDECYL ETHER (TRIDECETH-12), is prepared in demineralized water, heating and mixing if necessary to ensure the solubility and homogeneity of the solution (at 35°C or in an oven at 45°C). The vial to be tested is wetted with the cracking agent solution thus obtained, so that it is well impregnated both inside and outside. The closure capsule is placed on the bottle. The container to be tested is immersed in a crystallizer filled with the cracking agent solution so that the container to be tested and its stress zone are surrounded by the solution. The crystallizer is covered with a watch glass to prevent evaporation so that the items remain constantly immersed, then the oven is heated to 55°C + or – 2°C for 24 hours + or – 1 hour.

For the interpretation of the results, a visual examination of the tested container is carried out, any cracking observed being considered as a defect. If in doubt, color the cracked area with a non-permanent marker, then remove excess marker ink with paper towel. If the crack remains colored, it is indeed cracking and therefore a defect. To evaluate all the non-accessible stress zones, the operation and/or the behavior of the assembly is checked and then the presence of cracking zones is evaluated after dismantling. After returning to ambient temperature, a tightness test is also carried out on the tested container if no cracking zone is observed after dismantling.

The invention is not limited to the example which has just been described.

In particular, the wall 12 of the bottle 2 can comprise a number of layers different from six layers, being at least three. In the example shown in the , the wall 12 comprises only three layers, namely a barrier layer 15, an outer layer 16 and an inner layer 17.

Claims (12)

Bottle (2) intended to contain a product, in particular cosmetic, the bottle (2) being produced by a coextrusion-blow molding process and comprising a body (5) and a neck (6) surmounting the body (5) and defining an opening (7) of the bottle (2), the body (5) and the neck (6) being formed by a multilayer wall (12) of the bottle (2), the multilayer wall (12) of the bottle (2) comprising at least three superimposed layers including at least one barrier layer (15) interposed between an outer layer (16) and an inner layer (17), at least the inner layer (16) comprising a post-consumer recycled (PCR) polyolefin having a melt index of hot (MFI) between 0.50 and 0.85g/10 min (2.16kg/190°C/ATSM D1238 standard). A bottle (2) according to claim 1, wherein the outer layer (16) comprises a post-consumer recycled (PCR) polyolefin, which post-consumer recycled (PCR) polyolefin is preferably the same as the inner layer and/or comprises a hot melt index (MFI) between 0.55 and 0.85 g/10 min (2.16 kg/190°C/ATSM D1238 standard). Bottle (2) according to one of the preceding claims, in which the thickness of the outer layer (16) forms between 15% and 25%, preferably approximately 20%, of the total thickness of the multilayer wall (12). of the bottle (2). A bottle (2) according to any preceding claim, wherein the thickness of the inner layer (17) forms between 22% and 32%, preferably about 27%, of the total thickness of the wall ( 12) multilayer of the vial (2). Bottle (2) according to any one of the preceding claims, comprising an intermediate layer (18) located between the inner layer (17) and the barrier layer (15), the intermediate layer (18) comprising at least one ground material and one polyolefin post-consumer recycled (PCR), said post-consumer recycled (PCR) polyolefin being in particular the same as for the inner layer (17) and/or comprises a post-consumer recycled (PCR) polyolefin with a melt index (MFI) comprised between 0.55 and 0.85 g/10 min (2.16 kg/190°C/ATSM D1238 standard). Bottle (2) according to the preceding claim, in which the thickness of the intermediate layer (18) forms between 40% and 50% of the total thickness of the multilayer wall (12) of the bottle. Bottle (2) according to any one of the preceding claims, the multilayer wall (12) of the bottle (2) comprising two adhesive layers (19; 19a, 19b) arranged respectively on either side of the barrier layer (15) , in contact with it. A bottle (2) according to any preceding claim, wherein the post-consumer recycled (PCR) polyolefin is selected from the group consisting of post-consumer recycled (PCR) polyethylene (PE), including post-consumer recycled (HDPE) polyethylene (HDPE). consumption (PCR), and all types of polyethylene and mixture of polyethylenes. Bottle (2) according to the preceding claim, in which the recycled polyolefin is a post-consumer recycled (PCR) polyethylene, the density of the post-consumer recycled (PCR) polyethylene being between 0.95 and 0.97 g/cm ³ , preferably between 0.958 and 0.965 g/cm ³ . Container (1) comprising a bottle (2) according to any one of the preceding claims and a cap (3) for closing the bottle (2) configured to cooperate with the neck (6) of the bottle (2), in particular by screwing, so as to close the bottle (2) in leaktight manner, the closing cap (3) comprising a sealing skirt in contact with the interior side of the multilayer wall (12) of the bottle at the level of the neck (6), the The capsule (3) is preferably formed with a recycled polyolefin, in particular a post-consumer recycled (PCR) polypropylene, in particular by injection molding. Container (1) according to the preceding claim, the bottle (2) housing a hair coloring composition. Process for manufacturing a bottle (2) according to any one of Claims 1 to 8, comprising the steps consisting in coextruding and blowing said at least three layers into a mold to obtain the bottle (2) comprising the body (5 ) and the neck (6).